Motor control mechanism for electric clocks



May 29, 1934. A. wI FOWLER MOTOR CONTROL MECHANISM FOR ELECTRIC CLOCKS Filed Oct. 27, 1950 Patented May 29, 1934 PATENT FICE MOTOR CONTROL MECHANISM FOR ELECTRIC CLOCKS Arno W. Fowler, Highland, Ill.

Application October 27,

5 Claims.

This invention relates to motor control mechanism for electric clocks and more particularly to the type operated by a main spring kept in tension by an electric motor of the induction type, theperiods of the operation of the motor being controlled by frictional engaging mechanism.

` One of the objects of this invention is to provide improved mechanism for controlling the operation of the electric motor including devices cooperatively associated with the main spring whereby the motor is stopped after the spring is suiiiciently wound, and permitted tol start again after the spring is partially unwound.

Another object of the invention is to provide improved frictional control mechanism for frictionally stopping the motor automatically, and as an incident to the completion of the winding operation, and permitting automatically the rewinding of thel spring after it has been unwound.

Various other objects and advantages will appear from the following description taken in connection with the accompanying drawing, in which- Fig. 1 is a lateral side elevation of the mechanism.

Fig. 2 is a vertical sectional View of the mechanism taken on line 2 2, Fig. 1.

The time indication of the clock is by the minute hand, not shown on the drawing, but mounted on the shaft 1 in the usual manner and by an hour hand operated through a train of gearing in any usual and well known manner. The minute shaft 1 has secured to it a pinion 2 Which is driven by a circular rack 3 secured to and a part lof the spring barrel 4. The main spring 5 has one end secured to the barrel 4 and its other end secured to a shaft 6.

A gear 7 is secured to the shaft 6 and comprises means whereby through a train of gearing vthe main spring 5 may be wound by an electric motor 8, preferably of the shaded pole induction type. The motor may be supplied from any convenient source of alternating current through the leads 9.

The motor armature is secured to a shaft 10 to which is also secured the pinion 11 adapted to drive a gear 12 and with it, affixed to the same shaft 13, a pinion 14. The pinion 14 is in mesh with and drives a gear 15 and with it a pinion 16 1930, Serial No. 491,411

(Cl. 18E- 40) ing just described by rotating the gear 7 which is afxed to the shaft 6, the shaft 6 being secured to one end of the main spring 5.

A pawl 21, influenced by a spring 22, prevents rotation of the gear 7 in a direction opposite to that in which the gear is rotated by the operation of the motor.

The rotation of the minute shaft l may be regulated through an escapement mechanism and a train of gearing, not shown, operatively connected to a shaft 23. A pinion 24 is secured to the shaft 23 and is in mesh with a gear 25 secured to the shaft 1.

An elongated pinion 26 is xed to the shaft 1 and in mesh with a gear 27 having a hub internally threaded to engage helical threads 28 on the shaft 6. The arrangement is such that when the shaft 6 is rotated by operation of the motor through the train of gearing as described the gear 27 Will be held relatively against rotation through its engagement with the pinion 26 on the minute shaft 1 and thus will be moved longitudinally along the shaft 6. The arrangement of the gear 27 with relation to the train of gearing from the motor is such that in the travel of the gear 27 along the shaft 6 it will come into engagement with the gear 12, as clearly shown in Fig. 1. The result is that a braking effort will be produced on the train of gearing and thus the motor Will be started and stopped. With the rotation of the minute shaft the gear 27 will be rotated and moved out of engagement with the gear 12 to a position shown in dotted lines in Fig. 1. The motor will then be released and will rewind the spring, stopping when the gear 27 has been again brought into contact with the gear 12, as previously described.

rIhe pinion 2, the gear 25 and the pinion 26 have been described as fixed to the minute shaft 1. So far as concerns the mechanism involved in this invention, this statement is accurate, but as a matter of practice the pinion 2, the gear 25 and the pinion 26 are integral and are in frictional engagement only with the minute shaft 1. This frictional engagement permits the setting of the clock by moving the minute hand without disturbing the clock mechanism. Such a method of permitting frictional engagement between the indicating shaft and the clock mechanism is common practice.

The construction is such that the motor Will intermittently wind the main spring at frequent intervals in case there is no interruption of current. During normal operations the travel of the gear 27 laterally along the shaft 6 will be very small. The arrangement is such, however, that considerable travel is permitted and thus in the event of failure of the current supply the main spring will drive the time indicating means for a 5 comparatively long period.

It will thus be seen that mechanism has been provided, simple in construction and free from operating difculties, whereby the main spring of a clock may be kept wound by an electric motor,

the starting and stopping of the motor being accomplished automatically by frictional engaging mechanism.

It is obvious that parts of the invention may be used without the whole and that various changes may be made in the details of constructiony without departing from the spirit of this invention.

I claim:

1. Mechanism of the character described coinprising a shaft, helical threads on the shaft, a

main spring having one end secured tothe shaft, a motor, motion transmitting means whereby the motor may rotate the shaft and thereby wind the spring, a gear having a hub internally threaded screwed on the threads on said shaft, mechanism v operated by said spring, and including a shaft and an elongated pinion affixed to the shaft meshing with said gear throughout the extent of the travel of the gear along said first shaft, and means constituting an effective part of said transmission means in the path of travel of said gear whereby the gear may engage said means and brake the motor.

2. Mechanism of the character described comprising a shaft adapted to drive time indicating `means, a second shaft, a spring barrel loosely mounted on said second shaft, a spring having one end secured to said barrel and the other end secured to said second shaft, helical threads on said second shaft, an electric motor, transmission fmeans for driving said second shaft by the motor, a gear having a hub with internal threads screwed on said threaded portion of said second shaft, a pinion secured to said first named shaft and engaging said gear, a rack on said barrel adapted ste drive said first named shaft, and a gear constituting an effective part of said transmission means in the path of the travel of the gear located on said threaded shaft whereby movement of said gear along said threaded shaft will cause 5@ ja braking effort on the motor.

3. Mechanism of the character described comprising a shaft adapted to rotate a minute hand, a pinion secured to said shaft, a circular rack meshing with said pinion, a spring barrel rigid with said rack, a threaded shaft extending into said barrel, a spring having one end secured to said barrel and the other end to said threaded shaft, a gear having an internal threaded hub screwed on the threads on said threaded shaft, a pinion secured to said first shaft meshing with said gear, an alternating current induction motor, and a train of gearing whereby said threaded shaft may be rotated by said motor, said train of gearing having one of its effective gears in the path of movement of the first named gear along the threaded shaft whereby engagement between said two gears will cause a braking effort on the motor.

4. Mechanism of the character described comprising a shaft to be rotated, a rotary threaded shaft parallel with said first shaft, a gear mounted on and rotative about said threaded shaft as an axis while said threaded shaft remains stationary, gearing for rotating said first shaft by said gear, a spring connecting said gear with said threaded shaft for rotating said gear about said threaded shaft, mechanism for rotating said threaded shaft to wind said spring, a gear screwed on said threaded shaft, and a pinion attached to and rotated by said first shaft for rotating said second gear by said rst shaft and holding said second gear from substantial rotation with said threaded shaft when said threaded shaft is rotated to wind said spring as aforesaid, one part of said gearing being engageable by said second gear whenv said threaded shaft is rotated by said mechanism to cause a braking effort on said mechanism.

5. Mechanism of the character described com prising a shaft to be rotated, a pinion attached to and rotated by said shaft, a rotary threaded shaft parallel with said first shaft, a gear mounted on and rotative about said threaded shaft as an axis while said threaded shaft remains stationary, gearing for rotating said first shaft by said gear, a spring connecting said gear with said second shaft for rotating said gear about said threaded shaft, a gear screwed on said second shaft and permanently engaging said pinion, and mechanism for rotating said threaded shaft to wind said spring and move said second gear longitudinally along said threaded shaft into engagement with a part of said gearing to cause a braking effort on said mechanism that rotates with said threaded shaft.

ARNO W. FOWLER. 

